| Parameter |
Value |
| Designation |
C/2003 H1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-02-22T14:57:51.929280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:29Z |
| Obs used |
1890 |
| NEO |
- |
| M1 |
11.000 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2003-08-30.0000000 |
| e |
0.99915679 |
| q (au) |
2.239626 |
| a (au) |
2656.070310 |
| i (deg) |
138.667213 |
| Ω (om, deg) |
19.000486 |
| ω (w, deg) |
196.139594 |
| M (ma, deg) |
359.998728 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.871 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.871 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.730 |
| k |
0.800 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2003-04-24 |
2004-02-21 |
+3.5205 |
-2.057 |
| 2004-02-23 |
2005-02-07 |
+17.2256 |
-6.015 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
01:51:53.95 |
+04:09:26.8 |
HIP 8668 |
4.17 |
| 2026-09-20 12:00 |
01:51:51.58 |
+04:09:12.2 |
HIP 8668 |
3.53 |
| 2026-09-21 00:00 |
01:51:49.19 |
+04:08:57.6 |
HIP 8668 |
2.89 |
| 2026-09-21 12:00 |
01:51:46.79 |
+04:08:42.9 |
HIP 8668 |
2.24 |
| 2026-09-22 00:00 |
01:51:44.38 |
+04:08:28.2 |
HIP 8668 |
1.59 |
| 2026-09-22 12:00 |
01:51:41.96 |
+04:08:13.5 |
HIP 8668 |
0.95 |
| 2026-09-23 00:00 |
01:51:39.52 |
+04:07:58.7 |
HIP 8668 |
0.32 |
| 2026-09-23 12:00 |
01:51:37.08 |
+04:07:43.9 |
HIP 8668 |
0.41 |
| 2026-09-24 00:00 |
01:51:34.62 |
+04:07:29.1 |
HIP 8668 |
1.05 |
| 2026-09-24 12:00 |
01:51:32.15 |
+04:07:14.3 |
HIP 8668 |
1.71 |
| 2026-09-25 00:00 |
01:51:29.67 |
+04:06:59.4 |
HIP 8668 |
2.38 |
| 2026-09-25 12:00 |
01:51:27.18 |
+04:06:44.6 |
HIP 8668 |
3.04 |
| 2026-09-26 00:00 |
01:51:24.68 |
+04:06:29.7 |
HIP 8668 |
3.71 |
| 2026-09-26 12:00 |
01:51:22.17 |
+04:06:14.8 |
HIP 8668 |
4.39 |
| 2026-09-27 00:00 |
01:51:19.64 |
+04:05:59.9 |
HIP 8668 |
5.06 |
| 2026-09-27 12:00 |
01:51:17.11 |
+04:05:44.9 |
HIP 8668 |
5.74 |
| 2026-09-28 00:00 |
01:51:14.57 |
+04:05:30.0 |
HIP 8668 |
6.42 |
| 2026-09-28 12:00 |
01:51:12.02 |
+04:05:15.0 |
HIP 8668 |
7.11 |
| 2026-09-29 00:00 |
01:51:09.45 |
+04:05:00.0 |
HIP 8668 |
7.79 |
| 2026-09-29 12:00 |
01:51:06.88 |
+04:04:45.0 |
HIP 8668 |
8.48 |
| 2026-09-30 00:00 |
01:51:04.30 |
+04:04:30.0 |
HIP 8605 |
8.78 |
| 2026-09-30 12:00 |
01:51:01.71 |
+04:04:15.0 |
HIP 8605 |
8.99 |
| 2026-10-01 00:00 |
01:50:59.11 |
+04:04:00.0 |
HIP 8605 |
9.25 |
| 2026-10-01 12:00 |
01:50:56.50 |
+04:03:44.9 |
HIP 8605 |
9.56 |
| 2026-10-02 00:00 |
01:50:53.89 |
+04:03:29.9 |
HIP 8605 |
9.90 |
| 2026-10-02 12:00 |
01:50:51.26 |
+04:03:14.8 |
HIP 8605 |
10.28 |
| 2026-10-03 00:00 |
01:50:48.63 |
+04:02:59.8 |
HIP 8605 |
10.70 |
| 2026-10-03 12:00 |
01:50:45.98 |
+04:02:44.7 |
HIP 8605 |
11.14 |
| 2026-10-04 00:00 |
01:50:43.33 |
+04:02:29.7 |
HIP 8605 |
11.61 |
| 2026-10-04 12:00 |
01:50:40.68 |
+04:02:14.6 |
HIP 8605 |
12.11 |
| 2026-10-05 00:00 |
01:50:38.01 |
+04:01:59.6 |
HIP 8605 |
12.62 |
| 2026-10-05 12:00 |
01:50:35.34 |
+04:01:44.5 |
HIP 8605 |
13.16 |
| 2026-10-06 00:00 |
01:50:32.66 |
+04:01:29.5 |
HIP 8605 |
13.71 |
| 2026-10-06 12:00 |
01:50:29.98 |
+04:01:14.5 |
HIP 8605 |
14.28 |
| 2026-10-07 00:00 |
01:50:27.28 |
+04:00:59.4 |
HIP 8605 |
14.86 |
| 2026-10-07 12:00 |
01:50:24.58 |
+04:00:44.4 |
HIP 8605 |
15.45 |
| 2026-10-08 00:00 |
01:50:21.88 |
+04:00:29.4 |
HIP 8605 |
16.05 |
| 2026-10-08 12:00 |
01:50:19.16 |
+04:00:14.4 |
HIP 8605 |
16.67 |
| 2026-10-09 00:00 |
01:50:16.45 |
+03:59:59.4 |
HIP 8605 |
17.29 |
| 2026-10-09 12:00 |
01:50:13.72 |
+03:59:44.4 |
HIP 8605 |
17.92 |
| 2026-10-10 00:00 |
01:50:10.99 |
+03:59:29.4 |
HIP 8605 |
18.56 |
| 2026-10-10 12:00 |
01:50:08.26 |
+03:59:14.5 |
HIP 8605 |
19.20 |
| 2026-10-11 00:00 |
01:50:05.52 |
+03:58:59.6 |
HIP 8605 |
19.86 |